7 Реши уравнения с комментированием и сделай проверку: a) 8.a - 6045 = 1963; б) 1475 - x: 12 = 275; в) 92 : (3.b + 5) = 4; г) (240 : x + 48) : 26 = 2.

а) 8 × a – 6045 = 1963

1. 8 × a = 1963 + 6045
2. 8 × a = 8008
3. a = 8008 ∶ 8
4. a = 1001

Проверка:

1. 8 × 1001 – 6045 = 1963
2. 8008 – 6045 = 1963
3. 1963 = 1963

б) 1475 – x ∶ 12 = 275

1. x ∶ 12 = 1475 – 275
2. x ∶ 12 = 1200
3. x = 1200 × 12
4. x = 14400

Проверка:

1. 1475 – 14400 ∶ 12 = 275
2. 1475 – 1200 = 275
3. 275 = 275

в) 92 ∶ (3 × b + 5) = 4

1. 3 × b + 5 = 92 ∶ 4
2. 3 × b + 5 = 23
3. 3 × b = 23 – 5
4. 3 × b = 18
5. b = 18 ∶ 3
6. b = 6

Проверка:

1. 92 ∶ (3 × 6 + 5) = 4
2. 92 ∶ (18 + 5) = 4
3. 92 ∶ 23 = 4
4. 4 = 4

г) (240 ∶ x + 48) ∶ 26 = 2

1. 240 ∶ x + 48 = 2 × 26
2. 240 ∶ x + 48 = 52
3. 240 ∶ x = 52 – 48
4. 240 ∶ x = 4
5. x = 240 ∶ 4
6. x = 60

Проверка:

1. (240 ∶ 60 + 48) ∶ 26 = 2
2. (4 + 48) ∶ 26 = 2
3. 52 ∶ 26 = 2
4. 2 = 2

Ответ: а) a = 1001; б) x = 14400; в) b = 6; г) x = 60.